1. Field of the Invention
The present invention applies to road or floor saws and more specifically to self-propelled operator-guided or steerable saws supported on a frame with wheels.
2. Description of the Related Art
In the concrete industry, when building bridges, buildings, roads and the like, it is often necessary to pour large horizontal slabs of concrete. Once poured, it is usually necessary to machine the slab. Such machining may include cutting seams completely through the slab (to form expansion joints and to allow for foundation shifting), cutting notches partially into the slab (to create stress cracks along which the slab will split), cutting multiple grooves into the slab to create a high friction surface such as for bridges, grinding the surface of the slab and the like. Concrete saws are also used in the demolition or removal of concrete, such as during the sawing and replacement of bridge decks. Various types of concrete saws may be utilized to carry out these machining and demolition tasks. In larger industrial applications, large self-propelled saws are used that are powered in a variety of manners, such as by gasoline, diesel, electric, propane and natural gas engines mounted on the saw. While performing a cut, the operator controls the direction, cutting speed, cutting depth and the like.
Recently designed concrete saws may include an engine that is mounted with its longitudinal axis in line with the longitudinal axis of the saw. This is in contrast to traditional transverse mounting arrangements. This new arrangement allows the saw to be moved through doorways and other passages that were previously not passable. Even with such an improvement, modern saws lack flexibility in other areas. Transmissions presently in use comprise a number of belts that are subject to wear and breakage, and belts require regular re-tensioning. These belt-driven transmissions do not provide a “neutral” configuration where the transmission is engaged, but the saw blade is not being driven except by means of a conventional clutch that is subject to wear. Often these transmissions operate at only a single speed, and if a multiple speed transmission is provided, it does not afford sequential shifting which avoids over-speeding a blade by accidentally shifting to a very high gear. Also, the prior art transmissions do not provide the convenience of being able to shift gears during the cutting operation (i.e., “on the fly”).
Therefore, there exists a need in the art for an improved road or floor saw which includes a transmission with more operational flexibility. Moreover, there exists a need in the art for a concrete saw that is low maintenance that provides a multi-speed transmission.